I need help with b. please.

Determining Retained Earnings and Net Income Using the Balance Sheet

The following information is reported for Kinney Corporation at the end of 2013.

Accounts Receivable $23,000

Retained Earnings$

Accounts Payable $11,000

Supplies Inventory $9,000

Cash $8,000

Equipment $138,000

Common Stock $110,000

a. Compute the amount of retained earnings at the end of 2013.

$57,000

b. If the amount of retained earnings at the beginning of 2013 was $30,000, and $12,000 in cash dividends were declared and paid during 2013, what was its net income for 2013?

I cannot figure this one out.